The value of g is more in the poles of the earth, why?

Explanation:

beacuse the poles are the cause of graIt's due to the rotation of earth about its own axis. Due to the rotation, objects placed on the surface of earth also rotates . Their rotational kinetic energy prevents them from the free fall along gravitational pull. This phenomena can also be explained sitting on the earth surface as their free fall suffers a centrifugal barrier due to the rotation. In this explanation, the term, centrifugal barrier, appears because earth is a non-inertial frame. Centrifugal force in a non intertial frame acts opposite to gravitational force.

The rotational energy / centrifugal barrier on a object depends on the radius of the circle linearly ; the circle is drawn around the axis of rotation from the point where the object placed. Now you can imagine that its radius get shorter and shorter towards the pole from the equator. Hence the barrier decreases if we move from equator to the both poles of earth. Hence garvitational force on a object i.e. its weight, so the g, becomes effectively maximum on the poles and minimum on the equator.

it is given that trillions of microbes make up to 1% to 3% of the body mass.

let's take average of this percentage: 2%

consider the average mass of the human body as 70 kg.

then, trillions of microbes would have mass  

therefore, 100 trillion micro-organisms would weigh:

this is an approximate value and could change depending on the mass of the human body and percentage of the microbes present in it.

average mass per microorganism =